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                [Usaco2006 Dec]Wormholes 虫洞                </h1>
                <p>时间限制：5s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：64MB</p>			</div>
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                                <h3>题目描述</h3><p><p><span style="font-size: medium">John在他的农场中闲逛时发现了许多虫洞。虫洞可以看作一条十分奇特的有向边，并可以使你返回到过去的一个时刻（相对你进入虫洞之前）。John的每个农场有M条小路（无向边)连接着N （从1..N标号）块地，并有W个虫洞。其中1&lt;=N&lt;=500,1&lt;=M&lt;=2500,1&lt;=W&lt;=200。 现在John想借助这些虫洞来回到过去（出发时刻之前），请你告诉他能办到吗。 John将向你提供F(1&lt;=F&lt;=5)个农场的地图。没有小路会耗费你超过10000秒的时间，当然也没有虫洞回帮你回到超过10000秒以前。 </span></p></p><hr/><h3>输入格式</h3><p><p><span style="font-size: medium">* Line 1: 一个整数 F, 表示农场个数。 </span></p>
<p><span style="font-size: medium">* Line 1 of each farm: 三个整数 N, M, W。</span></p>
<p><span style="font-size: medium"> * Lines 2..M+1 of each farm: 三个数（S, E, T）。表示在标号为S的地与标号为E的地中间有一条用时T秒的小路。</span></p>
<p><span style="font-size: medium"> * Lines M+2..M+W+1 of each farm: 三个数（S, E, T）。表示在标号为S的地与标号为E的地中间有一条可以使John到达T秒前的虫洞。</span></p></p><hr/><h3>输出格式</h3><p><p><span style="font-size: medium">* Lines 1..F: 如果John能在这个农场实现他的目标，输出&quot;YES&quot;,否则输出&quot;NO&quot;。 </span></p></p><hr/><h3>样例输入</h3><pre>2
3 3 1
1 2 2
1 3 4
2 3 1
3 1 3
3 2 1
1 2 3
2 3 4
3 1 8

</pre><hr/><h3>样例输出</h3><pre>NO
YES
</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>Gold</p>
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